ITMO20070354A1 - APPARATUS AND METHOD FOR DECORATING OBJECTS - Google Patents

Description

Apparatus and method for decorating objects

The invention relates to an apparatus and a method for decorating objects, in particular for decorating flat objects, such as ceramic tiles.

Apparatuses are known for decorating ceramic tiles comprising an inkjet printing device which can be fed with decorating materials containing ceramic pigments.

The aforesaid apparatuses comprise a conveying device, for example provided with a belt or belts, which supports and moves the ceramic tiles. The ink-jet printing device is arranged above the conveyor device and deposits the decorating materials on the ceramic tiles - defining a predetermined ornamental motif - while the tiles, moved by the conveyor device, pass under the ink-jet printing device.

To obtain ceramic tiles, it is foreseen to press a ceramic material in powder to obtain raw ceramic tiles, to dry the raw ceramic tiles - in drying devices - to promote the escape of water contained in the ceramic mixture in powder. Subsequently, it is foreseen to apply ceramic glazes in a liquid state on one face of the tiles destined to be visible after laying. The ceramic glazes form a layer on which the aforementioned ink-jet printing device deposits the decorating materials.

The ceramic glazes and decorating materials are deposited on the raw ceramic tiles as soon as the latter come out of the drying devices and, therefore, have a high temperature.

Subsequently, the raw ceramic tiles are introduced into kilns where they undergo a heat treatment that consolidates the ceramic material in powder to obtain a base body of the ceramic tiles and fixes the ceramic glazes and decorating materials to the aforementioned base body.

Ceramic glazes consist of an aqueous suspension of finely ground glass particles mixed with other ceramic raw materials and additives.

A defect of the apparatuses described above is that the ceramic glazes, when they come into contact with the raw ceramic tiles having a high temperature, tend to evaporate. On the dispensing nozzles of the ink-jet printing device, therefore, drops are deposited which prevent a correct transfer of the decorating materials. In addition, the aforementioned drops can fall on the tiles that pass under the ink-jet printing device, causing defects on the finished product.

In addition, particles of the additives that make up ceramic glazes - carried by the vapor - can damage, for example corrode, the ink-jet printing device.

To limit the aforementioned drawbacks, it is provided to periodically stop the conveyor device to allow manual cleaning of the ink-jet printing device in order to remove the drops.

This involves high operating costs, as an operator must be provided who frequently cleans the ink-jet printing device. In addition, the efficiency of the aforesaid apparatuses is heavily penalized due to the interruptions of the operating cycle necessary for the cleaning operations.

An object of the invention is to improve decorating apparatuses, in particular for decorating flat objects, such as ceramic tiles.

A further object is to obtain a decorating apparatus, in particular for decorating flat objects, such as ceramic tiles, which is not subject to wear and which requires reduced supervision by an operator.

In a first aspect of the invention, a decorating apparatus is provided, comprising ink-jet printing means arranged to deliver at least one decorating product intended to decorate objects, characterized in that it also comprises transfer means arranged to receive said at least one decorating product by said inkjet printing means and depositing said at least one decorating product on said objects.

In a second aspect of the invention, a method for decorating objects is provided, comprising dispensing by means of ink-jet printing means at least one decorating product intended to decorate said objects, characterized in that it also comprises distributing said at least one decorating product on means of transferring and transferring said at least one decorating product from said transfer means to said objects.

Thanks to these aspects of the invention, it is possible to obtain a decorating apparatus in which the ink-jet printing means comprise printing heads which are not directly facing the objects, as occurs in known apparatuses, but are facing the transfer means. and are spaced from objects. It follows that the aforesaid heads do not tend to get dirty with - or to be damaged by - substances, in particular in the vapor state, coming from the objects.

Furthermore, since the aforesaid print heads are further away from the objects than in the apparatuses according to the state of the art, the vapors coming from the objects are dispersed into the surrounding environment and do not settle on the aforementioned print heads.

The invention can be better understood and implemented with reference to the attached drawings, which illustrate some exemplary and non-limiting forms of implementation in which:

Figure 1 is a perspective side view of a decorating apparatus;

Figure 2 is a perspective side view of a transfer belt of the decorating apparatus of Figure 1;

Figure 3 is a schematic side view of a decorating machine comprising the decorating apparatus of Figure 1 cooperating with further decorating apparatuses;

Figure 4 is an enlarged and partially sectioned detail of Figure 3.

With reference to Figures 1 and 2, a decorating apparatus 1 arranged for decorating flat objects, such as ceramic tiles 2, is shown.

The decorating apparatus 1 comprises a conveyor device 3 arranged to move the ceramic tiles 2. The conveyor device 3 comprises a conveyor belt 4 closed in a loop around a drive roller and at least one driven roller. The drive roller drives the conveyor belt 4 along a direction of advance D. As an alternative to the conveyor belt 4, the conveyor device 3 can comprise a plurality of belts.

The decorating apparatus 1 further comprises an ink-jet printing device 5 positioned above the conveyor device 3 and provided with printing heads which deliver decorating products 6 containing ceramic pigments.

The decorating apparatus 1 further comprises a transfer device 7 arranged to receive the decorating products 6 from the ink-jet printing device 5 and to deposit the decorating products 6 on a face 8 of the ceramic tiles 2, the face 8 being intended to result in view after laying the ceramic tiles 2.

The transfer device 7 comprises a tubular transfer element, for example a transfer belt 9 closed in a loop on a first roller 10 and a second roller 11, the first roller 10 acting as a driving roller and the second roller 11 acting as a driving roller. postponement, or vice versa.

In one version, the decorating products dispensed by the ink-jet printing device 5 can be inks for ink-jet printers comprising ceramic pigments.

The decorating products 6 can comprise a first decorating product of cyan color, a second decorating product of red color, a third decorating product of yellow color and a fourth decorating product of black color.

In this case, the ink-jet printing device 5 can work with a four-color printing mode.

In another version, the decorating products supplied by the ink-jet printing device 5 can be traditional ceramic decorators, of the type applicable by known silk-screen, flexographic or engraving machines. Traditional ceramic decorating products can comprise a mixture formed by a vehicle in the liquid state in which a ground base product (containing ceramic raw materials and glass products) and one or more powdered pigments are dispersed. In this case, each decorating product can have a predetermined color which depends on the type and quantity of the aforementioned pigments. In other words, each decorating product can be made in accordance with a corresponding recipe to obtain a desired chromatic effect.

The ink-jet printing device comprises a plurality of groups of dispensing nozzles, for example a first group of dispensing nozzles 32a arranged to dispense a decorating product of a first color, a second group of dispensing nozzles 32b arranged to dispense a decorating product of a second color, a third group of dispensing nozzles 32c arranged to dispense a decorating product of a third color and a fourth group of dispensing nozzles 32d arranged to dispense a decorating product of a fourth color. In versions not shown, the number of groups of dispensing nozzles can be other than four.

The first group of dispensing nozzles 32a, the second group of dispensing nozzles 32b, the third group of dispensing nozzles 32c and the four group of dispensing nozzles 32d define four rows of nozzles. The aforesaid four rows of nozzles are arranged substantially horizontally and at different vertical heights, so as to be superimposed. Each group of nozzles forms on the transfer belt 9 a portion of a decoration which must be reproduced on the ceramic tiles 2. In particular, a decoration portion made by a group of dispensing nozzles does not substantially overlap a further decoration portion made by a further group of dispensing nozzles. In other words, a group of dispensing nozzles deposits a decorating product of a certain color in a zone of the transfer ribbon 9 and further groups of decorating nozzles deposit further decorating products of further colors in zones of the transfer ribbon 9 different from the aforesaid zone.

Alternatively, a decorating product deposited by a group of decorating nozzles can at least partially overlap a further decorating product deposited by a further group of dispensing nozzles.

The decorating apparatus 1, using a single ink-jet printing device 5, allows to obtain the same effect as an engraving decorating machine - for example of the type that will be described below - comprising a plurality of ribbons, or rollers, positioned applicators in succession along a direction of advancement of the ceramic tiles, each ribbon, or roller, applicator being arranged to deposit a decorating product of a certain color in a predetermined area of the aforesaid ceramic tiles. The decorating apparatus 1 allows to carry out manufacturing tests of ceramic tiles 2 in a laboratory, or directly in a production line, simulating the effect of an engraving decorating machine equipped with a plurality of tapes, or rollers, applicators arranged one of followed by the other along a direction of advancement of the ceramic tiles.

At the end of the aforesaid manufacturing tests, once a ceramic tile having a desired aesthetic appearance has been obtained, it is possible to prepare the applicator belts, or rollers, of an engraving decorating machine to carry out a series production with the aforesaid engraving machine. In this way, only the tapes, or rollers, applicators intended for series production have to be prepared, for example engraved by laser, and not the tapes, or rollers, applicators necessary for manufacturing tests. This allows to obtain a considerable reduction in costs since, during the manufacturing tests, it is necessary, proceeding by trial and error, to prepare a large number of test applicator tapes, or rollers, having a high unit cost, which, a once laser engraved, they cannot be recycled.

The apparatus 1, therefore, can be installed in an existing production line and equipped with an engraving decorating machine - or in a laboratory of an existing plant and in which an engraving decorating machine is installed to allow optimization of the management of the engraving. engraving decorating machine.

Alternatively, the entire series production can be carried out with the decorating apparatus 1, in particular in the case of small batches for which the preparation of applicator belts, or rollers, could prove to be uneconomical.

In a further version, it is possible to provide an ink-jet printing device and, upstream or downstream of it, a known type of decorating machine, for example a screen printing, flexo or engraving decorating machine, as will be described in greater detail below. . This allows you to obtain a combined decoration mode.

With reference to Figure 2, the transfer belt 9 comprises a first toothed belt 16 and a second toothed belt (not shown) fixed to an internal surface 17 of the transfer belt 9 at opposite end areas of the transfer belt 9. The first toothed belt 16 and the second toothed belt are arranged to engage with toothed portions provided at opposite ends of the first roller 10 and second roller 11, or with toothed pulleys fixed at opposite ends of the first roller 10 and second roller 11.

The first roller 10 is rotatable - in a direction of rotation R - around a first axis of rotation A1 and the second roller 11 is rotatable - in the direction of rotation R - around a second axis of rotation A2. The first roller 10 and the second roller 11 are positioned in such a way that the first axis of rotation A1 and the second axis of rotation A2 identify a substantially vertical plane. The transfer ribbon 9 is positioned in such a way that, at each instant of an operating cycle of the decorating apparatus 1, it is possible to identify a first portion 9a of the transfer ribbon 9 facing towards the ink-jet printing device 5 and a second portion 9b of the transfer belt 9 facing away from the ink-jet printing device 5. The first portion 9a and the second portion 9b are arranged transversely - in particular substantially perpendicularly - with respect to the conveyor belt 4 and to the direction of advancement D.

The ink-jet printing device 5 is positioned in such a way that the printing heads emit jets of decorating products 6 substantially parallel to the direction of advance D.

The ink-jet printing device 5 produces on the transfer ribbon 9 a decorating pattern 12 formed by the decorating products 6, while the transfer tape 9 moves with respect to the ink-jet printing device 5.

During the operation of the decorating apparatus 1, the transfer belt 9 and the conveyor belt 4 are operated synchronously. In other words, the transfer belt 9 is moved at a movement speed equal to a forward speed at which the conveyor belt 4 moves. Consequently, the transfer belt 9 interacts with the ceramic tiles 2 supported by the conveyor belt 4. without creeping with respect to the ceramic tiles 2. In this way, the transfer tape 9 transfers the decorator motif 12 onto the face 8 without the decorator motif 12 being altered or damaged.

The second roller 11 acts as a pressing element which presses the transfer ribbon 9 against the face 8.

Since the ink-jet printing device 5 is arranged at a considerable distance from the conveyor belt 4, gaseous particles generated by the evaporation of ceramic glazes which have been deposited on the ceramic tiles 2 by dispensing devices positioned upstream of the decorating apparatus 1 are dispersed in the surrounding environment before interacting with the print heads of the ink-jet printing device 5.

This prevents the formation of drops on the print heads of the ink-jet printing device 5. Furthermore, this prevents vapors - possibly containing acid substances - from interacting with the ink-jet printing device 5 corroding it.

Since the gaseous particles are dispersed before reaching the ink-jet printing device 5, it is not necessary to stop the operation of the decorating apparatus 1 to carry out cleaning operations, in particular to remove the drops from the printing heads. Any drops formed on an external casing of the ink-jet printing device can be removed without stopping the operation of the decorating apparatus 1.

The transfer belt 9 can be made of deformable material, in particular elastomeric material such as silicone rubber, so as not to damage the ceramic tiles 2 if they are raw and, therefore, very fragile.

The elastomeric material is impermeable to decorating products 6 and water-repellent.

In addition, the transfer belt 9, being made of deformable material - that is, being very soft - can adequately deposit the decorating products 6 even on tiles having a non-planar face 8. In particular, it is possible to decorate ceramic tiles having faces 8 provided with ridges and depressions obtained by pressing the ceramic material in powder with molds equipped with a corrugated active surface, in order to give the ceramic tiles 2 an appearance similar to that of natural materials, for example example natural stones.

The transfer belt 9 comprises a transfer surface 13, intended to receive the decorating products 6, which can be smooth or provided with a screening, in particular a substantially uniform screening which occupies the entire transfer surface 13, which favors the adhesion of the decorating products 6 to the transfer belt 9 and hinders a displacement of the decorating products 6 with respect to the transfer belt 9, before the decorating products 6 are transferred to the ceramic tiles 2.

The decorating apparatus 1 further comprises detection means (not shown) - for example photocell detection means - which detect the presence of a ceramic tile 2 to be decorated on the conveyor belt 4 and control the ink-jet printing device 5.

The decorating apparatus 1 further comprises cleaning means 14 arranged to remove from the transfer belt 9 residues of decorating products 6 that have not been transferred onto the ceramic tiles 2. In order to adequately decorate the edge areas of the ceramic tiles 2 it is possible to produce on the belt transfer 9 a decorator motif 12 having dimensions slightly larger than those of the face 8. In this case, the aforementioned residues originate from the quantities of decorator products 6 which form the portions of the decorator motif 12 which protrude from the face 8 and therefore remain on the transfer ribbon 9 when the transfer ribbon 9 interacts with the ceramic tiles 2.

The cleaning means 14 comprise a cleaning roller 15 facing the second portion 9b of the transfer belt 9.

As an alternative to the cleaning roller 15, a doctor blade can be provided.

In combination with the cleaning roller 15, or with the doctor blade, a nebulizer device can be provided which is arranged to nebulize a liquid on the transfer belt 9 to promote the removal of the aforementioned residues.

With reference to Figure 3, a decorating machine 30 is shown comprising a decorating apparatus 1 of the type described with reference to Figures 1 and 2 and a plurality of further decorating apparatuses 20. The decorating apparatuses 20 are engraving decorating apparatuses.

The further decorating apparatuses 20 are arranged one after the other along the direction of advance D. The decorating apparatus 1 is arranged downstream of the further decorating apparatuses 20 along the direction of advancement D.

Each further decorating apparatus 20 comprises a further transfer belt 21 closed in a loop on a further first roller 22 and a further second roller 23, the further first roller 22 acting as a drive roller and the further second roller 23 acting as a return roller , or viceversa.

Similarly to what has been described with reference to Figure 2, each further transfer belt 21 comprises a further first toothed belt 24 and a further second toothed belt (not shown) fixed to a further internal surface 25 of the further transfer belt 21 in correspondence with opposite end zones of the further transfer belt 21. The first further toothed belt 24 and the second further toothed belt are arranged to engage with toothed portions provided at opposite ends of the further first roller 22 and of the further second roller 23, or with toothed pulleys fixed to opposite ends of the further first roller 22 and of the further second roller 23.

The further first roller 22 is rotatable - in the direction of rotation R - around a further first axis of rotation B1 and the further second roller 23 is rotatable - in the direction of rotation R - around a further second axis of rotation B2. The further first roller 22 and the further second roller 23 are positioned in such a way that the further first axis of rotation B1 and the further second axis of rotation B2 identify a substantially vertical plane.

The further transfer ribbon 21 is positioned in such a way that, at each instant of an operating cycle of the further decorating apparatus 20, it is possible to identify a further first portion 21a of the further transfer ribbon 21 and a further second portion 21b of the further transfer belt 21 arranged transversely - in particular substantially perpendicular to the conveyor belt 4 and to the direction of advance D.

The further transfer belt 21 can be made of deformable material, in particular elastomeric material such as silicone rubber.

The further transfer belt 21 comprises a further transfer surface 26 provided with a plurality of cavities 27 arranged to receive a decorating material 28, having a fluid consistency.

The cavities 27 are arranged in such a way as to create a design which must be reproduced on the ceramic tiles 2.

The cavities 27 can be obtained by engraving, for example by means of a laser engraving device, the further conveyor belt 21.

Each further decorating apparatus 20 further comprises a doctor blade 29 arranged to interact with the further transfer surface 26 in such a way as to distribute the decorator material 28 inside the cavities 27 and to remove the decorator material 28 from the further transfer surface 26. excess.

Each decorating apparatus 20 further comprises a supply duct 31 arranged to feed the decorating material 28 upstream of the doctor blade 29. During the operation of the further decorating apparatus 20, while the further transfer belt 26 is driven by the motor roller, the doctor blade 29 distributes the decorator material 28 inside the cavity 27. Subsequently, when the further transfer belt 21 interacts with the ceramic tiles 2 supported and moved by the conveyor belt 4, the cavities 27 deposit the decorator material 28 on the face 8. The decorating machine 30 is very versatile, since it allows to combine an engraving decoration technique, obtained with the further decorating apparatuses 2, and an ink-jet decorating technique, obtained with the decorating apparatus 1.

In particular, each further decorating apparatus 20 can create on the ceramic tiles 2 a pattern having a predetermined color, after which the decorating apparatus 1 produces a decorating motif 12 - monochromatic or polychromatic - which can be varied with extreme ease by means of a control device and control which controls the ink-jet printing device 5. In particular, a plurality of decorative motifs 12 can be stored in digital form in the command and control device. In this way, it is possible to obtain ceramic tiles 2 which differ from each other.

In addition, the decorating machine 30 can use only the ink-jet printing technique, keeping the further decorating apparatuses 20 in an inoperative condition and activating the decorating apparatus 1, or only the engraving printing technique, keeping in a non-operative condition. the ink-jet printing device 5 is operative and the further decorating devices 20 are activated. tape provided with cavity 27) and arrange the doctor blade 29 and the supply duct 31 in an operative configuration. In this case, the decorating machine 1 is, in fact, equipped with a further engraving printing unit, which allows ceramics 2 a further application of decorator material 28.

The replacement of the transfer ribbon 9 with the further transfer ribbon 21 is very simple as it is sufficient to approach each other the first roller 10 and the second roller 11, remove the transfer ribbon 9, insert the further transfer ribbon 21 and mutually move away the first roller 10 and the second roller 11.

Claims (34)

CLAIMS 1. Decorating apparatus, comprising ink-jet printing means (5) arranged to deliver at least one decorating product (6) intended to decorate objects (2), characterized in that it further comprises transfer means (7) arranged to receive said at least a decorating product (6) from said ink-jet printing means (5) and depositing said at least one decorating product (6) on said objects (2). 2. Decorating apparatus according to claim 1, wherein said objects comprise ceramic articles (2). 3. Decorating apparatus according to claim 1, or 2, wherein said inkjet printing means (5) deposit a decorating product (6) having a predetermined color in a zone of said transfer means (7) and a further decorating material ( 6) having a further color in a further zone of said transfer means (7) other than said zone. 4. Decorating apparatus according to one of the preceding claims, wherein said ink-jet printing means (5) comprise groups of dispensing nozzles (32a, 32b, 32c, 32d), each of said groups of dispensing nozzles (32a, 32b, 32c , 32d) being arranged to dispense a decorating product (6) having a predetermined color. 5. Decorating apparatus according to one of the preceding claims, wherein said transfer means (7) comprise transfer belt means (9). 6. Decorating apparatus according to claim 5, wherein said transfer belt means (9) are made of deformable material. 7. Decorating apparatus according to claim 5, or 6, wherein said transfer belt means (9) comprises a smooth transfer surface (13) intended to receive said at least one decorating product (6). 8. Decorating apparatus according to claim 5, or 6, wherein said transfer belt means (9) comprise a screened transfer surface (13) intended to receive said at least one decorating product (6). Decorating apparatus according to one of claims 5 to 8, wherein said transfer means (7) comprise cleaning means (14) arranged to remove from said transfer belt means (9) residues of said at least one decorating product (6). 10. Decorating apparatus according to claim 9, wherein said cleaning means comprises a cleaning roller (15). 11. Decorating apparatus according to claim 9, wherein said cleaning means comprises a cleaning doctor blade. Decorating apparatus according to one of claims 9 to 11, wherein said cleaning means (15) further comprise dispensing means arranged to deliver a fluid onto said transfer belt means (9). 13. Decorating apparatus according to one of claims 5 to 12, wherein said transfer belt means comprise a closed loop belt (9). Apparatus according to claim 13, wherein said closed loop belt (9) extends between a drive roller (10) and a deflection roller (11), said drive roller (10) and said deflection roller (11) being arranged in a substantially vertical plane. 15. Decorating apparatus according to one of the preceding claims, and further comprising conveyor means (3) arranged to move said objects (2) along a direction of advancement (D) and to bring said objects to interact with said transfer means (7). 16. Decorating apparatus according to claim 15, when dependent on one of claims 5 to 14, in which said transfer belt means (9) are arranged transversely with respect to said conveyor means (3) and to said direction of advancement (D) . 17. Decorating apparatus according to claim 16, wherein said transfer belt means (9) are arranged substantially perpendicular to said conveyor means (3) and to said direction of advance (D). 18. Decorating apparatus according to one of claims 15 to 17, wherein said ink-jet printing means (5) comprise dispensing nozzle means (32a, 32b, 32c, 32d) positioned in such a way as to deliver jets of said at least one decorating product (6) substantially parallel to said direction of advancement (D). 19. Decorating apparatus according to one of the preceding claims, and further comprising further transfer means (21) arranged to deposit decorating material (28) on said objects (2). 20. Decorating apparatus according to claim 19 when dependent on one of claims 15 to 18, wherein said further transfer means (21) are arranged upstream of said transfer means (7) with respect to said direction of advancement (D) . 21. Decorating apparatus according to claim 19, or 20, wherein said further transfer means (27) comprise further transfer belt means (21) provided with cavities (27) arranged to receive said decorator material (28) and to deposit said decorating material (28) on said objects (2). 22. Decorating apparatus according to claim 21, and further comprising doctor blade means (29) arranged to introduce said decorating material (28) into said cavity (27) and to remove from said further transfer belt means (21) an excess of said decorator material (28). 23. Method for decorating objects (2), comprising dispensing by means of ink-jet printing means (5) at least one decorating product (6) intended to decorate said objects (2), characterized in that it further comprises distributing said at least one decorating product (6) onto transfer means (9) and transferring said at least one decorating product (6) from said transfer means (9) to said objects (2). Method according to claim 23, wherein said objects comprise ceramic articles (2). Method according to claim 23, or 24, wherein said dispensing comprises depositing a decorating product (6) having a predetermined color in an area of said transfer means (7) and a further decorating material (6) having a further color in a further zone of said transfer means (7) other than said zone. Method according to one of claims 23 to 25, wherein said transfer means (7) comprise transfer belt means (9). Method according to claim 26, wherein said transfer belt means (9) are made of deformable material. Method according to claim 26 or 27, and further comprising removing from said transfer belt means (9) residues of said at least one decorating product (6). 29. Method according to one of claims 23 to 28, and further comprising moving said objects (2) by means of conveyor means (3) along a direction of advancement (D) to bring said objects to interact with said transfer means (7). 30. Method according to claim 29 when dependent on one of claims 26 to 28, wherein said transfer belt means (9) are arranged transversely with respect to said conveyor means (3) and said feed direction (D). A method according to claim 30, wherein said transfer belt means (9) are arranged substantially perpendicular to said conveyor means (3) and to said feed direction (D). 32. Method according to one of claims 29 to 31, and further comprising positioning dispensing nozzles (32a, 32b, 32c, 32d) of said ink-jet printing means (5) in such a way as to deliver jets of said at least one decorating product (6) substantially parallel to said feed direction (D). Method according to one of claims 23 to 32, and further comprising further distributing decorating material (28) on said objects (2) by further transfer means (21) comprising further transfer belt means (21) provided with cavities ( 27) arranged to receive said decorating material (28) and to deposit said decorating material (28) on said objects (2). 34. A method according to claim 33, wherein said depositing occurs prior to said transferring.